The sequence of some regular proteins, when correlated with other structural information, such as data from x-ray diffraction, fiber diffraction, electron microscopy, and spectroscopic analysis, can be used to evaluate models of protein or polymer structure. Four current studies involve the sequence analysis of keratin and other intermediate filaments (with NIAMS); computer models of biopolymers (with PSL, DCRT), and analysis of protein sequences from viruses and bacterial (with NIAMS), and new methods to analyze one-dimensional gel electrophoresis images (with NCRR and NIAMS). As the complete sequence of keratin, other intermediate filaments, and other helical proteins become available, an analysis of the sequence can proceed by studying periodicities in the sequence, and by computer prediction of the conformational properties of the specific amino acids in local regions of the chain. These predictions can be used to generalize structures where related sequences are available, and to draw conclusions as to similarities and differences. This year a number of analyses are providing useful information into the structure of proteins. The analysis of the amino acid sequence of the Sigma-1 protein from reovirus, as well as images of the proteins has recently been published. We have been able to correlate specific features in the sequence with features in images obtained from correlation alignment and correlation averaging of single fibers. As new sequences of regular (helical) proteins become available, it will be relatively easy to model these sequences and describe their structures both graphically and quantitatively.